Android 修改系统关机动画的实现

private static void beginShutdownSequence(Context context) {  ...... 3   // throw up an indeterminate system dialog to indicate radio is  // shutting down.  //*********************** 系统默认的Dialog  ***********************  /*ProgressDialog pd = new ProgressDialog(context);  pd.setTitle(context.getText(com.android.internal.R.string.power_off));  pd.setMessage(context.getText(com.android.internal.R.string.shutdown_progress));  pd.setIndeterminate(true);  pd.setCancelable(false);  pd.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);  pd.show();*/  //*********************** 替换为自定义的全屏Dialog  ***********************  Point outSize = new Point();  Dialog dialog = new Dialog(context, android.R.style.Theme_Black_NoTitleBar_Fullscreen);  IndeterminateProgressBar view = new IndeterminateProgressBar(context);  dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);  dialog.getWindow().getWindowManager().getDefaultDisplay().getSize(outSize); //获取屏幕宽高  dialog.setContentView(view, new LayoutParams(outSize.x, outSize.y));     //设置自定义view宽高为全屏  dialog.show();    ......}

class IndeterminateProgressBar extends View {  static final String TAG = "ProgressBar";  private int delayMillis = 30;  private Handler mHandler;  private ArrayList<Entity> entities;  private int width = 0;  // private int height = 0;  private int r = 15;  private int shift = 20;  private int radius = 3;  private int color = Color.WHITE;  private long time = 0;  private boolean started = false;  public IndeterminateProgressBar(Context context) {    super(context);    init();  }  @Override  protected void onLayout(boolean changed, int left, int top, int right,      int bottom) {    super.onLayout(changed, left, top, right, bottom);    width = getLayoutParams().width / 2;    // height = getLayoutParams().height;    if (width > 0) {      radius = width / 20;      r = 2 * width / 5;      //shift = width / 2;      shift = width / 1;    }  }  private void init() {    setBackgroundResource(android.R.color.transparent);    mHandler = new Handler(new Handler.Callback() {      @Override      public boolean handleMessage(Message msg) {        for (Entity e : entities) {          e.update();        }        invalidate();        mHandler.sendEmptyMessageDelayed(0, delayMillis);        time += delayMillis;        return false;      }    });  }  public void setColor(int color) {    this.color = color;  }  public void stop() {    mHandler.removeMessages(0);    started = false;    invalidate();  }  public boolean isStart() {    return started;  }  public void start() {    if (started)      return;    started = true;    time = 0;    entities = new ArrayList<IndeterminateProgressBar.Entity>();    float s = .25f;    entities.add(new Entity(0, color, 0));    entities.add(new Entity(1 * s, color, delayMillis * 4));    entities.add(new Entity(2 * s, color, delayMillis * 8));    entities.add(new Entity(3 * s, color, delayMillis * 12));    entities.add(new Entity(4 * s, color, delayMillis * 16));    // entities.add(new Entity(5 * s, color, delayMillis * 20));      if (mHandler != null)        mHandler.sendEmptyMessage(0);    }    @Override    protected void onDraw(Canvas canvas) {      if (entities != null && entities.size() > 0) {        for (Entity e : entities) {          e.draw(canvas);        }      }      super.onDraw(canvas);    }    class Entity {      private float x;      private float y;      private int color;      private Paint paint;      private double sp = 0;      private long delay;      private int sec = 0;      private float pec = 0;      boolean visiable = true;      public float getInterpolation(float input) {        return (float) (Math.cos((input + 1) * Math.PI) / 2.0f) + 0.5f;      }      public Entity(float sp, int color, int delay) {        paint = new Paint();        paint.setAntiAlias(true);        paint.setStyle(Paint.Style.FILL);        this.color = color;        this.sp = sp;        this.delay = delay;        paint.setColor(this.color);      }      public void update() {        if (time < delay)          return;        visiable = true;        pec += 0.03;        if (pec > 1) {          pec = 0;          sec = ++sec == 3 ? 0 : sec;          delay = sec == 0 ? time + delayMillis * 22 : time + delayMillis              * 3;          visiable = sec == 0 ? false : true;        }        double θ = Math.PI            * .5            + (sec == 0 ? 0 : sec * Math.PI / sec)            - (sec == 0 ? 0 : sp)            + (Math.PI * (sec == 1 ? 2 : 1) - (sec == 0 ? sp : 0) + (sec == 2 ? sp                : 0)) * getInterpolation(pec);        x = (float) (r / 2 * Math.cos(θ)) + shift / 2;        y = (float) (r / 2 * Math.sin(θ)) + shift / 2;      }      public void draw(Canvas canvas) {        if (!visiable || x == 0 || y == 0)          return;        canvas.save();        canvas.translate(x, y);        canvas.drawCircle(x, y, radius, paint);        canvas.restore();      }    }    @Override    protected void onAttachedToWindow() {      super.onAttachedToWindow();      if (getVisibility() == View.VISIBLE) {        start();      }    }    @Override    protected void onDetachedFromWindow() {      super.onDetachedFromWindow();      stop();    }    public void setDelayMillis(int delayMillis) {      this.delayMillis = delayMillis;    }}